1. Field of the Invention
The invention relates to an integrated circuit having a plurality of driver stages, in which blocking capacitors suppress electromagnetic emission (EME) as a result of switching operations of the drivers onto the supply voltage lines.
2. Description of the Related Art
In order to reduce the electromagnetic emission of integrated circuits, large on-chip capacitances of the order of magnitude of, for example, 1 to 10 nF are integrated. These blocking capacitances serve for smoothing the supply voltages or as an energy reserve, in particular for strong drivers. Their effect is all the better, the larger the capacitances or the lower the impedance with which they are connected. Therefore, as far as possible every free chip area of a semiconductor component is utilized for forming these blocking capacitances. Enlarging these blocking capacitors by means of a larger chip area or, alternatively, by means of thinner or special dielectrics means increased costs. Added to this is the fact that ever more compact layouts are being produced by ever better design tools, which means fewer and fewer free areas for such blocking capacitances.
The invention is based on the object, then, of specifying a device for reducing the electromagnetic emission in integrated circuits having a plurality of driver stages, in which the electromagnetic emission is reduced as far as possible without increasing the capacitance of the blocking capacitors.
This object is achieved according to the invention by means of the features of patent claim 1. The rest of the claims relate to advantageous refinements of the invention.